Methods of forming a tang-receiving recess in wooden handles for knives or other tools or the like



3,014,512 -METHODS F FORMlNr A TMG-RECEIVING RECESS IN WOODEN HANDLES FOR KNIVES OR OTHER TOOLS OR THE LIKE u Carl Follie Mller', Eskilstuna, Sweden, assigner to VAktiebolaget Bahco, Stockholm, Sweden, a corporation of Sweden Filed Jan. 26, 1960, Ser. No. 4,810 Claims priority, application Sweden Feb. 18, 1959 Z Claims. (Cl. 14d-321) The present invention relates to a method of forming in wooden handles Vfor knives andy other tools a recess adapted to receive a tang of the knife or other tool.

Hitherto it has been customary to manufacture such handles in two` halves which by milling have been provided with grooves corresponding to the knife tang and have then been riveted together with the inserted tang. Attempts have also beenl made to form the necessary tangreceiving recess in the handle without dividing it, and usually these methods have comprised providing the handle with a longitudinal bore for inserting a scraper for mechanically removing the additional woodL material required to obtain a recess corresponding to the usuallyllat strip-like tang. klt has also been suggested to mill a longitudinal groove in one face of the handle and then cover said groove with glued wooden stick so that only so much. is left of the milled groove as corresponds to the knife tang. The lirst-mentioned method does not result in a neat handle. The second method is expensive and results in a recess extending along the entire length of the handle, which mars the appearance of the handle. The third method too, results `in an unsatisfactory appearance of the handle.

lt will also be observed that it lhas been suggested to use wooden handles entirely' enclosed by a metal sleeve. ln that case the knife tang can be driven into the wooden handle which thereby may crack, but will be held together by the metal sleeve. Furthermore, it is well known to clamp the knife tang in awoodeu handle which is surrounded by a metal sleeve and is preliminarily provided with a longitudinal recess for the tang.

According to the present invention, it is possible without dividing the handle and without the use of a longitudinal bore to provide a recess in the wooden handle corresponding exactly to the knife tang in both width and thickness, without the necessity of surrounding the wooden handle with a metal sleeve. The invention comprises forming the recess in the 4handle for the knife tang byV driving a stamp or mandrel of a shape similar to that of the tang into the handle while this is restrainedpin all directions by a pressure suited to the particular kind of wood used in the handle.

It was found that in this operation'no cracks are formed in wooden handles, and instead the wood is subjected to a compression corresponding to the Volume of the recess whereby the strength and solidity of the wood are increased. lt is the step of restraining the handle while the stamp or mandrel is driven into the handle which renders this operation possible. rIt is ditlicult to indicate general numerical values for the force by which the handle is restrained but it was found that the greater the restraining force, the more satisfactory compression will be obtained and the less is the danger of cracking. However, an increased restraining force also necessitates an increased force for driving the stamp or mandrel into the handle, and it was found that with high restraining pressures the stamp can be heated by the friction energy to such an extent that the wood is burnt fast to the stamp. It was also found, at least for some kinds of Wood, that it is advantageous to apply a greater restraining force between two opposed faces of the handle than between the other two opposed 3,l4,5l2 Patented Dec. 26, 196i faces. Thus, if the recess for the knife tang is formed in a handle blank of rectangular cross-section it is in some cases preferable to apply a Vgreater restraining force between the two narrower faces of t-he wooden handle than between the two broader faces. The magnitude of the necessary restraining force also depends on the nature and type of the wood. The force with which the stamp must be driven into the handle is directly depending on the particular wood used and the restraining force. The hard African wood bubiuga which is often used for household knives requires a considerably greater stamp driving force than eg. beech wood which is usually employed in butcher knives. ln experiments, the restraining forces have in some cases been increased up to about 4 5 metric tons and the stamp driving force can for some kinds of hardwood ybe 3-10 tons. For softer and/ or more porous woods or for very big handles the restraining force and the stamp driving `force may be kept at much lower values,` e.g. a hundred or a few hundred kilograms.

Suitably, hydraulic power will be used for restraining the handle as well as for driving the stamp. On account of some shrinkage of the handle after removal of the knife tangV stamp, the stamp should suitably be made with slightly larger dimensions than the knife tang.

- rIn order that the stamp shall not be driven in an oblique direction into the handle, which may occur especially in the case of thin stamps, a hole may be bored preliminarily in the handle blank, in which case the stamp will be formed or provided at least at the end thereof with a pin which guides it in the bore.

It will be understood that the method of this inventionl is not limited toknife handles but is generally applicable to all sorts of handles.

The accompanying drawings serve to illustrate the method.

FIGURE l shows a knife with a handle, the latter being shownin longitudinal section.

FIGURE 2 shows a restrained bored handle blank in longitudinal section, a stamp being shown in an initial position for entering the blank.

FIGURE 3 is similar to FIGURE 2 but shows the stamp in its ultimate position.

FEGUR'E 4 is a cross-section taken along line lV-lV iin FIGURE 3 after removal of the stamp.

Referring to FIGURE l, the numeral .l designates the knife blade, 2 the tang and 3 the handle whichy has a recess d into which the tang is inserted, the recess l being formed by the method of this invention. The tang 2` an thereby the knife blade l are retained in the recess 4 by means of rivets 5 extendingthrough the handle and the tang.

As seen in FIGURES 2 and 4 the manufacture of the handle starts from a handle blank 6 of rectangular cress-y section which is restrained betweenjaws 7, 8, 9, ld of Y which the jaws 8 and 7 can be subjected to pressure independently of each other so that the restraining force is varied. lBefore the stamp lll is driven into the handle blank this is suitably provided with a bore 12 which is intended to guide the stamp ll while it is forced into the blank. For this purpose the stamp il at least at its lower end is provided with a guiding projection ld corresponding to the bore'lZ. FIGURE 3 shows the stamp driven completely into the handle blank restrained by the jaws.

To obtain the handle shown in FIGURE l the handle blank is further worked after withdrawal of the stamp and removal of the blank from the restraining jaws.

The shape of the stamp or mandrel can and must of course be varied in accordance with the shape of the particular tang.

l claim:

l. A method of making a knife-like tool having a wooden handle with a recess receiving the tang or" the tool', said tang having a predetermined shape lengthwise and an `irregular cross section, which comprises the steps of subjecting each pair of opposed sides of said handle to a suitable inwardly directed pressure independent of the pressure applied to other pairs of opposed sides by means of separate jaws applied to the handle sides and extending along a length at least equal to the depth of the recess to be formed, driving a stamp of a shape substantially conforming to the shape of and slightly larger than the tang into said handle while it is subjected to said pressures to compress the wood of the handle laterally until a recess of a shape complementary to the tang of said tool is formed in said handle, withdrawing said stamp from the handle, and inserting the tang of the knife-like tool into the complementary recess.

2. A method of making a knife-like tool having a wooden handle with a recess receiving the tang of the tool, said tang having a predetermined shape lengthwise and an irregular cross section, which com-prises the steps of forming a longitudinal guide -bore in said handle, subjecting each pair of opposed sides of said handle to a suitable inwardly directed pressure independent of the pressure applied to other pairs of opposed sides by means of separate jaws applied to the handle sides and extending along a length at least equal to the depth of the recess to be formed, driving a stamp having a guide projection guided by said bore and said stamp being of a shape substantially conforming to the shape of and slightly larger than the tang into said handle while it is subjected to said pressures to compress the wood of the handle laterally until a recess of a shape complementary to the tang of said tool is formed in said handle, withdrawing said stamp from the handle, and inserting the tang of the knife-like tool into the complementary recess.

References Cited in the file of this patent UNITED l STATES PATENTS Swan June 20, 1905 Salz Ian. 4, 1916 

